MinnFlyer,

Well,........ I was just giving my personal experience on what I have used. And yes, It is TRUE with my TME smoke pump I didnt need a restrictor valve and i tried it with and without one and I found that mine looked best without one. Now this was all at nearly 3/4 throttle or above but just about any gas engine can handle it with no restrictor. But I do agree with you if you, that a restrictor would be best if you are going to use smoke at times other than full throttle. I feel that the best way to go would be with one of the new sullivan or slimline pumps since you can mix the flow rate with your throttle which would give you the best flow rate for all throttle applications,

FUZZ